A two-dimensional catalyst of Fe2O3 loaded potassium-doped silver particles and a preparation method and application thereof
By using a two-dimensional catalyst with potassium-doped silver particles supported on Fe2O3, the problems of high energy consumption and limited activity in low-temperature reverse water gas conversion reaction have been solved, achieving efficient CO generation and promoting the development of low-temperature CO2 hydrogenation catalysts.
Patent Information
- Application Number
- CN202410449953.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-15
- Publication Date
- 2026-06-12
- Estimated Expiration
- 2044-04-15
AI Technical Summary
Existing low-temperature reverse water gas conversion catalysts suffer from high energy consumption and limited activity, especially transition metal-based catalysts, which struggle to outperform platinum group metal-based catalysts.
A two-dimensional catalyst, Fe2O3 supported on potassium-doped silver particles, was synthesized via a starch-assisted template method to form a mixture of Fe2O3 nanosheets, Ag clusters, and K single atoms for use in the reverse water gas conversion reaction, combined with heating or light energization.
High CO yield and selectivity were achieved at low temperatures. The Fe2O3-supported potassium-doped silver particle catalyst achieved a CO yield of 1029 mmol·g⁻¹·h⁻¹ at 300 °C and a CO generation rate of 1925.7 mmol·g⁻¹·h⁻¹ under photothermal catalysis, while maintaining 100% CO selectivity.
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Figure CN118320836B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of catalyst technology, specifically relating to a two-dimensional catalyst of Fe2O3 supported on potassium-doped silver particles, its preparation method, and its application. Background Technology
[0002] Reverse water gasification (RWGS, CO2 + H2 → CO + H2O) is a fundamental reaction for CO2 utilization because the resulting syngas (CO + H2) is a raw material for constructing high-value-added chemicals. RWGS requires high operating temperatures above 500°C, which not only increases the energy consumption of thermally catalytic RWGS but also limits the activity and availability of photothermal RWGS. This makes the research of efficient low-temperature RWGS catalysts a highly desirable research direction. Based on platinum group metals (Pt, Rh, Ru, Pd), a series of low-temperature RWGS catalysts have been developed. For example, Liu et al. synthesized synergistic interaction sites of Pt clusters and oxygen vacancies, demonstrating a CO production rate of 619.2 mmol.g. in RWGS at 300°C. -1 .h -1 This achieved a record-breaking performance. Due to the scarcity and high cost of platinum group metals (PGMs), they are difficult to produce in terms of both economy and scalability for RWGS catalysts. Through the efforts of scientists, some transition metal (e.g., Co, Ni, Mo)-based catalysts have exhibited catalytic properties similar to PGMs. Among them, transition metal carbides (Co₂C, Mo₂C) showed the best RWGS performance at 300 °C, with an RWGS CO formation rate of less than 260 mmol·g⁻¹. -1 .h -1 The CO selectivity is less than 97%. However, the overall RWGS performance of transition metal-based catalysts is still far inferior to that of platinum group metal-based catalysts. Therefore, researching new transition metal-based catalysts that can surpass platinum group metal-based catalysts in low-temperature RWGS performance is a highly challenging problem in catalysis science. Summary of the Invention
[0003] To address the aforementioned technical problems, this invention provides a two-dimensional catalyst with Fe2O3-supported potassium-doped silver particles, its preparation method, and its application.
[0004] One objective of this invention is to provide a two-dimensional catalyst for Fe2O3-supported potassium-doped silver particles, the formula of which is K. x Ag y / Fe2O3, x=0.01~0.7, y=0.01~0.7, the catalyst is a mixture of two-dimensional nanosheet Fe2O3, Ag clusters and K single atoms, and K single atoms are doped in Ag clusters.
[0005] The catalyst was synthesized by a starch-assisted template method, in which a certain amount of ferric nitrate, silver nitrate, potassium nitrate and water-soluble starch were added to water to form a homogeneous solution, which was then freeze-dried to remove moisture, and then the water-soluble starch was removed by air annealing.
[0006] The second objective of this invention is to provide a method for preparing the two-dimensional catalyst of Fe2O3 supported potassium-doped silver particles, specifically including the following steps:
[0007] Dissolve 10g of water-soluble starch, 4-200mg of AgNO3, 680-950mg of Fe(NO3)3·9H2O, and 2-120mg of KNO3 in water, stir well, and freeze dry to obtain the dried product.
[0008] The dried product was placed in a muffle furnace and heated to 420-430°C in air and held for 5-6 hours to obtain the two-dimensional catalyst of Fe2O3 supported on potassium-doped silver particles.
[0009] Furthermore, in the above method, the heating rate is 1℃·min. -1 .
[0010] The third objective of this invention is to provide the application of the two-dimensional catalyst, which consists of Fe2O3-supported potassium-doped silver particles, in the catalytic reverse water gas conversion reaction.
[0011] Furthermore, in the above applications, the energy-generating methods for the reverse water gas conversion reaction include heating or light irradiation.
[0012] Furthermore, the heating temperature is 15-300℃.
[0013] Furthermore, the light source includes one or more of sunlight, xenon lamps, LED lamps, tungsten lamps, and mercury lamps.
[0014] Furthermore, the power density of the illumination is 0.1-1 kW·m. -2 .
[0015] The third objective of this invention is to provide a method for a reverse water-gas conversion reaction, comprising the following steps:
[0016] Under the enabled conditions, CO2 and H2 undergo a reverse water-gas conversion reaction in the presence of the two-dimensional catalyst of potassium-doped silver particles supported on Fe2O3 to obtain CO.
[0017] Compared with the prior art, the present invention has the following beneficial effects:
[0018] Iron (Fe) is one of the most abundant metallic elements in the world and is generally considered a potentially inactive catalyst for Reactive WGS (Reactive Golden WGS) because its RWGS activity is limited by two high-energy-barrier steps: CO2 activation and CO desorption. In this invention, we discovered that adding alkali metals to the iron-silver series achieves superior low-temperature RWGS performance. Here, we prepared a starch-assisted template method to synthesize Fe2O3 nanosheets, Ag clusters, and K single atoms in a heterostructure (K... 0.15 Ag 0.05 / Fe2O3), whose RWGS at 300℃ showed 1029 mmol·g. -1 .h -1 The CO yield and 100% CO selectivity were achieved. Theoretical calculations show that the efficient activation of CO2 and the strong desorption of CO are jointly achieved by the K, Ag, and Fe2O3 interfaces. With the assistance of TiC / Cu-based photothermal devices, 2D K... 0.15 Ag 0.05 When the intensity of sunlight exposure increases to 1 sun, the photothermal RWGS CO formation rate of Fe2O3 reaches 1925.7 mmol.g. -1 .h -1 Furthermore, the CO selectivity remained at 100%. This work demonstrates that alkali metal and Ag modification provides a new approach for constructing platinum group metal-free low-temperature CO2 hydrogenation catalysts. Based on the low-temperature CO2 hydrogenation activity, 2DK 0.15 Ag 0.05 / Fe2O3 can be photo-driven, achieving carbon neutralization driven by natural sunlight. Attached Figure Description
[0019] Figure 1 K before reaction 0.15 Ag 0.05 SEM of Fe2O3.
[0020] Figure 2 K after the reaction 0.15 Ag 0.05 SEM of Fe2O3.
[0021] Figure 3 K before reaction 0.15 Ag 0.05 TEM of Fe2O3.
[0022] Figure 4 K after the reaction 0.15 Ag 0.05 TEM of Fe2O3.
[0023] Figure 5 K before reaction 0.15 Ag 0.05The elemental distribution mapping image of / Fe2O3, A is the bright field image, B is the Fe elemental distribution, C is the O elemental distribution, D is the Ag elemental distribution, and E is the K elemental distribution.
[0024] Figure 6 K after the reaction 0.15 Ag 0.05 The elemental distribution mapping image of / Fe2O3, A is the bright field image, B is the Fe elemental distribution, C is the O elemental distribution, D is the Ag elemental distribution, and E is the K elemental distribution.
[0025] Figure 7 K before reaction 0.15 Ag 0.05 XRD image of Fe2O3.
[0026] Figure 8 K after the reaction 0.15 Ag 0.05 XRD image of Fe2O3.
[0027] Figure 9 K before reaction 0.15 Ag 0.05 XPS images of Fe2O3, A is the XPS spectrum of Fe 2P region, and B is the XPS spectrum of Ag 3d region.
[0028] Figure 10 K after the reaction 0.15 Ag 0.05 XPS images of Fe2O3, A is the XPS spectrum of Fe 2P region, and B is the XPS spectrum of Ag 3d region.
[0029] Figure 11 For K 0.15 Ag 0.05 RWGS performance of Fe2O3 (A) and CO selectivity (B). Detailed Implementation
[0030] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments, but this should not be construed as limiting the invention. Unless otherwise specified, the technical means used in the following embodiments are conventional means well known to those skilled in the art, and the materials, reagents, etc. used in the following embodiments are commercially available unless otherwise specified.
[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
[0032] In this invention, the technical features described in an open-ended manner include both closed-ended technical solutions composed of the listed features and open-ended technical solutions that include the listed features.
[0033] In this invention, numerical ranges are involved, and unless otherwise specified, they include the two endpoints of the numerical range.
[0034] Unless otherwise specified, the temperature parameters in this invention allow for both constant-temperature treatment and treatment within a certain temperature range, with room temperature being 20-25°C. The constant-temperature treatment allows temperature fluctuations within the precision range controlled by the instrument.
[0035] Example 1: 2D K 0.01 Ag 0.01 Preparation and characterization of Fe2O3
[0036] 10 g of water-soluble starch, 4.2 mg of AgNO3, 993 mg of Fe(NO3)3·9H2O, and 2.5 mg of KNO3 were dissolved in 400 mL of water. After stirring for 0.5 hours, the homogeneous solution was dropped into liquid nitrogen to rapidly freeze it into ice, and then freeze-dried at -52 °C for 48 hours to remove H2O. The dried product was then heated in a muffle furnace at 425 °C (heating rate 1 °C / min). -1 Calcination at 0.5°C for 5 hours yielded a product named 2D K. 0.01 Ag 0.01 / Fe2O3.
[0037] Example 2: 2D K 0.15 Ag 0.05 Preparation of Fe2O3
[0038] 10 g of water-soluble starch, 20 mg of AgNO3, 945 mg of Fe(NO3)3·9H2O, and 35 mg of KNO3 were dissolved in 400 mL of water. After stirring for 0.5 hours, the homogeneous solution was dropped into liquid nitrogen to rapidly freeze it into ice, and then freeze-dried for 48 hours to remove H2O. The dried product was then heated in a muffle furnace at 425 °C (heating rate 1 °C / min). -1 Calcination for 5 hours yielded a product named 2DK. 0.15 Ag 0.05 / Fe2O3.
[0039] Example 3: 2D K 0.5 Ag 0.5 Preparation of Fe2O3
[0040] 10 g of water-soluble starch, 157 mg of AgNO3, 749 mg of Fe(NO3)3·9H2O, and 94 mg of KNO3 were dissolved in 400 mL of water. After stirring for 0.5 hours, the homogeneous solution was dropped into liquid nitrogen to rapidly freeze it into ice, and then freeze-dried for 48 hours to remove H2O. The dried product was then heated in a muffle furnace at 425 °C (heating rate 1 °C / min). -1 Calcination for 5 hours yielded a product named 2DK. 0.5 Ag 0.5 / Fe2O3.
[0041] Example 4: 2D K 0.7 Ag 0.7 Preparation of Fe2O3
[0042] 10 g of water-soluble starch, 200 mg of AgNO3, 680 mg of Fe(NO3)3·9H2O, and 120 mg of KNO3 were dissolved in 400 mL of water. After stirring for 0.5 hours, the homogeneous solution was dropped into liquid nitrogen to rapidly freeze it into ice, and then freeze-dried for 48 hours to remove H2O. The dried product was then heated in a muffle furnace at 425 °C (heating rate 1 °C / min). -1 Calcination for 5 hours yielded a product named 2DK. 0.7 Ag 0.7 / Fe2O3.
[0043] To demonstrate the beneficial effects of the present invention, K prepared in Example 2 was used. 0.15 Ag 0.05 Taking Fe2O3 as an example, its use as a catalyst in the thermocatalytic hydrogenation of CO2 to produce CO follows the specific steps:
[0044] The thermocatalytic activity of the carbon dioxide hydrogenation catalyst was tested in a continuous flow configuration using a fixed-bed reactor (XM190708-007, Dalian Zhongjialin Liquid Technology Co., Ltd.). A thermocatalytic RWGS experiment was conducted by loading 5 mg of catalyst into a quartz tube at a temperature of 300 °C and a feed gas flow rate of 30 mL / min. -1 CO2 and 60 mL / min -1 A mixture of H2. The reaction products were detected using a gas chromatograph (GC) 7890A equipped with FID and TCD detectors.
[0045] The aforementioned two-dimensional catalyst was synthesized using a starch-assisted template method. Quantitative amounts of ferric nitrate, silver nitrate, potassium nitrate, and water-soluble starch were added to water to form a homogeneous solution. The solution was freeze-dried for 48 hours to remove moisture, followed by air annealing to remove the water-soluble starch. Figure 1-4 This shows the K before and after the reverse water gas reaction. 0.15 Ag 0.05Typical scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images of Fe2O3, showing the catalyst growing in a two-dimensional nanosheet morphology. Additionally, elemental distribution mapping images ( Figure 5 and Figure 6 This study confirmed the presence of oxygen (O), iron (Fe), silver (Ag), and potassium (K) throughout the sample. Interestingly, silver and potassium clusters were observed, and the catalyst remained unchanged after the reaction compared to the original catalyst. To visualize the Ag, Fe, and K species, high-angle dark-field scanning TEM (HAADF-STEM) was employed. Both pre- and post-reaction TEM images showed the presence of K. 0.15 Ag 0.05 The sample exhibits typical Fe2O3 (311) crystal planes on a 2D substrate and Ag (200) crystal planes on clusters within Fe2O3. Furthermore, numerous bright spots are observed on the sample surface. Since no potassium-related features are present in the XRD pattern, these bright spots are attributed to potassium single atoms, indicating a highly uniform distribution of potassium on the support. This confirms that the catalyst is a mixture of 2D Fe2O3, Ag clusters, and K single atoms. Powder X-ray diffraction (XRD) patterns also confirm the presence of metallic Ag and Fe2O3. Figure 7 , 8 The results were consistent with those of macroscopic X-ray photoelectron spectroscopy (XPS). The XPS spectra further confirmed the oxidation state of Fe and the metallic state of Ag. Figure 9 , 10 ).
[0046] To further illustrate the beneficial effects of the present invention, a comparative example is also provided, as follows:
[0047] Comparative Example 1: 2D K 0.15 Ag 0.05 Preparation of Al2O3
[0048] 10 g of water-soluble starch, 21 mg of AgNO3, 941 mg of Al(NO3)3·9H2O, and 38 mg of KNO3 were dissolved in 400 mL of water. After stirring for 0.5 hours, the homogeneous solution was dropped into liquid nitrogen to rapidly freeze it into ice, and then freeze-dried for 48 hours to remove H2O. The dried product was then heated in a muffle furnace at 425 °C (heating rate 1 °C / min). -1 Calcination at 0.5°C for 5 hours yielded a product named 2D K. 0.15 Ag 0.05 / Al2O3.
[0049] Comparative Example 2: 2D K 0.15 Preparation of Fe2O3
[0050] 10 g of water-soluble starch, 964 mg of Fe(NO3)3·9H2O, and 36 mg of KNO3 were dissolved in 400 mL of water. After stirring for 0.5 hours, the homogeneous solution was dropped into liquid nitrogen to rapidly freeze it into ice, and then freeze-dried for 48 hours to remove H2O. The dried product was then heated in a muffle furnace at 425 °C (heating rate 1 °C / min). -1 Calcination for 5 hours yielded a product named 2D K. 0.15 / Fe2O3.
[0051] Comparative Example 3: 2D Ag 0.05 Preparation of Fe2O3
[0052] 10 g of water-soluble starch, 980 mg of Fe(NO3)3·9H2O, and 20 mg of AgNO3 were dissolved in 400 mL of water. After stirring for 0.5 hours, the homogeneous solution was dropped into liquid nitrogen to rapidly freeze it into ice, and then freeze-dried for 48 hours to remove H2O. The dried product was then heated in a muffle furnace at 425 °C (heating rate 1 °C / min). -1 Calcination for 5 hours yielded a product named 2D Ag. 0.05 / Fe2O3.
[0053] Comparative Example 4: Preparation of 2D Fe2O3
[0054] 10g of water-soluble starch and 1g of Fe(NO3)3·9H2O were dissolved in 400mL of water. After stirring for 0.5 hours, the homogeneous solution was dropped into liquid nitrogen to rapidly freeze it into ice, and then freeze-dried for 48 hours to remove H2O. The dried product was then heated in a muffle furnace at 425℃ (heating rate 1℃.min). -1 The product was calcined for 5 hours and named 2D Fe2O3.
[0055] Application Example 1: RWGS Catalytic Efficiency of Different Catalysts
[0056] The 2D K prepared in Example 1 0.15 Ag 0.05 / Fe2O3, 2DK prepared in Comparative Example 1 0.15 Ag 0.05 / Al2O3, 2D K prepared in Comparative Example 2 0.15 / Fe2O3, 2D Ag prepared in Comparative Example 3 0.05 Fe2O3, 2D Fe2O3 prepared in Comparative Example 4, and Ag nanoparticles (denoted as Ag) were used as catalysts for the thermocatalytic hydrogenation reaction of CO2 to produce CO.
[0057] For fair comparison, we set an activation temperature where the RWGS CO yield was above 1 mmol·g. -1 .h -1 Temperature. 2D K 0.15 Ag 0.05 The RWGS activation temperature of Fe2O3 is 200℃, while pure Fe and pure Ag are inactive throughout the entire reaction temperature range. Figure 11 a). Furthermore, the active metal Fe was replaced with the inactive metal Al (defined as 2D K). 0.15 Ag 0.05 / Al2O3,) and removing Ag elements (defined as 2D K) 0.15 The comparative experiments of Fe2O3 showed weak RWGS activity, indicating that excellent RWGS activity only occurs when Fe, Ag, and K are present together. This confirms that the combined effect of iron-silver catalyst and alkali metal promotes the enhancement of RWGS activity.
[0058] In addition, 2D K 0.15 Ag 0.05 The CO yield of Fe₂O₃ reached 1029 mmol / g at 300 °C. -1 .h -1 CO selectivity is 100% Figure 11 b) The CO2 conversion efficiency is 7%, compared to 2D K 0.15 Ag 0.05 / Al2O3 and 2D K 0.15 Compared to Fe2O3, it exhibits higher activity (2D K). 0.15 Ag 0.05 The CO yield of Al₂O₃ at 300℃ is 2.94 mmol.g -1 .h -1 2D K 0.15 The CO yield of Fe₂O₃ at 300℃ is 1.323 mmol / g. -1 .h -1 (All selectivity is 100%).
[0059] Application Example 2: Light-Driven RWGS Efficiency
[0060] 5mg 2D K 0.15 Ag 0.05 / Fe2O3-injected TiC / Cu-based photothermal device (0.036m) 2 The experiment was conducted at room temperature (approximately 25°C) using natural sunlight as the light source. In this experiment, the flow rate of the feed gas was 30 mL / min. -1 CO2 and 60mL min -1A mixture of H2. The reaction products were detected using a gas chromatograph (GC) 7890A equipped with FID and TCD detectors. Results showed that the photothermal RWGS CO formation rate reached 1925.7 mmol·g when the sunlight intensity increased to 1 sun. -1 .h -1 Furthermore, CO selectivity remained at 100% throughout.
[0061] It should be noted that when numerical ranges are mentioned in the claims of this invention, it should be understood that the two endpoints of each numerical range and any value between the two endpoints can be selected. To avoid redundancy, the present invention describes preferred embodiments.
[0062] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.
[0063] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.
Claims
1. A two-dimensional catalyst supported on Fe2O3 and doped with potassium silver particles, characterized in that, Its expression is K x Ag y / Fe2O3, x=0.01~0.7, y=0.01~0.7, the catalyst is a mixture of two-dimensional nanosheet Fe2O3, Ag clusters and K single atoms, and K single atoms are doped in Ag clusters.
2. The two-dimensional catalyst with potassium-doped silver particles supported on Fe2O3 according to claim 1, characterized in that, The catalyst was synthesized using a starch-assisted template method.
3. The method for preparing the two-dimensional catalyst of Fe2O3 supported on potassium-doped silver particles as described in claim 2, characterized in that, Includes the following steps: Dissolve 10g of water-soluble starch, 4-200 mg of AgNO3, 680-950 mg of Fe(NO3)3·9H2O, and 2-120 mg of KNO3 in water, stir well, and freeze dry to obtain the dried product. The dried product was heated to 420-430℃ in air and held for 5-6 hours to obtain the two-dimensional catalyst of Fe2O3 supported potassium-doped silver particles.
4. The method for preparing the two-dimensional catalyst of Fe2O3 supported potassium-doped silver particles according to claim 3, characterized in that, The heating rate is 1℃ / min. -1 .
5. The application of the two-dimensional catalyst of Fe2O3 supported on potassium-doped silver particles as described in any one of claims 1-2 in the catalytic reverse water gas conversion reaction, characterized in that, Under the enabled conditions, and with the action of the two-dimensional catalyst of potassium-doped silver particles supported on Fe2O3, CO2 and H2 undergo a reverse water-gas conversion reaction to obtain CO.
6. The application according to claim 5, characterized in that, The energy-generating methods for the reverse water gas conversion reaction include heating or light irradiation.
7. The application according to claim 6, characterized in that, The heating temperature is 200-300℃.
8. The application according to claim 6, characterized in that, The light source includes one or more of sunlight, xenon lamps, LED lamps, tungsten lamps, and mercury lamps.
9. The application according to claim 8, characterized in that, The power density of the illumination is 0.1-1 kW·m⁻¹ -2 .